Data messages may be transmitted between two or more systems, and due to the data content, size, transmission, and receiving environment, or the like, may be received in an order different that transmitted, e.g. out of sequence. Current queue based message handlers may use a single processing element, or consumer, for sequential processing of related messages, e.g. messages relating to a sequence of events. These message handlers can ensure the sequential integrity of the processing of the related messages, but not the processing order of the messages. Further, some queue based message handlers utilizing the single processing element are inefficient in regard to unrelated messages which may be unnecessarily blocked from transmission, e.g. stored in the queue during the processing of the related messages. The existing message handlers fail to provide a process for intelligently blocking related, e.g. dependent, message transmission until the completion of the prior message processing, while letting unrelated, e.g. non-dependent, messages be processed and transmitted.